Terahertz (THz) and millimeter wavelength radiation are useful for a variety of imaging applications. For example, millimeter wave scanners may be used for whole-body imaging, such as for loss prevention, smuggling, and security screening. THz radiation may be used for similar applications including material characterization, layer inspection, and other forms of imaging (e.g., as an alternative to X-rays).
Certain challenges exist when designing and implementing such systems. For example, transmitting millimeter wave and THz signals over waveguides requires expensive ridged waveguides that are machined. However, manufacturing of such complex systems requires machining individual parts and assembling them together. Yet, at these high frequencies, the size of the devices becomes very small, and machining and assembly becomes difficult.
Various devices have been developed for transmitting signals in the THz and millimeter range. One example is set forth in U.S. Pat. Pub. No. 2008/0025680 to Sun et al. This publication discloses a plastic waveguide for guiding terahertz (THz) waves with a wavelength ranging from 30 to 3000 μm. The plastic waveguide includes a core and a cladding layer. At least part of the core is made of a first plastic medium having a first refractive index, and the maximum length of a cross-section of the core is smaller than the wavelength of the guided terahertz wave. The cladding layer surrounds the core and has a second refractive index lower than the first refractive index. Only one wave mode is propagated in the plastic waveguide, and a first attenuation constant of the core for the guided terahertz wave is higher than a second attenuation constant of the cladding layer for the guided terahertz wave.
Despite the existence of such devices, further enhancements may be desirable, such as to provide relatively easier and cost effective manufacturing capabilities.